在函数中使用循环 [英] Using a Loop Inside a Function

问题描述

我仍然在学习功能以及它们如何工作。我知道我在做什么错，而不是如何解决它。我正在写一个函数，将图像数据从数据库中提取出来并返回到屏幕上。它可以工作，但是如果有多个图像，它将只返回最后一个图像。我知道问题是因为while循环的作用， $ project_image 只返回最后一张图片，但我的问题是我怎么不能使用while循环或使它为 $ project_image 变量添加了多个图片。

$ b

缩减功能

 函数get_project_image（$ id，$ type =thumb，$ src =false，$ limit = 1）{
 if（$ type ==main）{
 $ project_image_qry = mysql_query（SELECT i_name FROM`project_images` WHERE i_project_id ='$ id'AND i_type ='2'LIMIT $ limit）or die （mysql_error（））; 
 $ project_image =; 
 while（$ project_image_row = mysql_fetch_array（$ project_image_qry））{
 $ project_image_result = mysql_fetch_array（$ project_image_qry）; 
 $ b $ if（$ src ==true）{
 $ project_image。='< img src =''。admin_settings（'site_url'）。admin_settings（'image_main_dir'）。 '/'.$project_image_result['i_name']。'alt =project_image/>'; 
} 
 else {
 $ project_image。= $ project_image_result ['i_name']; 
} 
} 
} 
 return $ project_image; 
 
  

解决方案

您的而条件很好，但是您似乎在两次获取中，在 $ project_image_row 和 $ project_image_result ，所以你会跳过其他图像。只需一次获取数组（在while循环中是好的），并使用 $ project_image_result 而不是 $ project_image_row 循环引用该数组：

pre $ while（$ project_image_result = mysql_fetch_array（$ project_image_qry））{
if（$ src ==true）{
$ project_image。='< img src =''。admin_settings（'site_url'）。admin_settings（'image_main_dir'）。'/'。$ project_image_result ['i_name'] ''alt =project_image/>';
}
else {
$ project_image。= $ project_image_result ['i_name'];


$ / code $ / pre



另外，它似乎默认情况下告诉它只从数据库请求一个图像。您有一个默认参数 $ limit = 1 ，并且您使用SQL LIMIT 来过滤结果，所以除非您将第四个参数传递给 get_project_image mysql_query 只返回一个结果（您没有包含调用 get_project_image ，所以我不确定你是否处理了这个问题。

I'm still learning functions and how they work. I know what I'm doing wrong just not how to fix it. I am writing a function to pull image data out of a database and return it onto the screen. It works but if there is more than one image it will return the last image only. I know the problem is that $project_image is only returning the last image because of the way the while loop works but my question is how can i either not use a while loop or make it add more than one image to the $project_image variable.

Abridged Function

   function get_project_image($id,$type="thumb",$src="false",$limit=1){
    if($type =="main"){
        $project_image_qry = mysql_query(" SELECT i_name FROM `project_images` WHERE i_project_id = '$id' AND i_type= '2' LIMIT $limit " ) or die(mysql_error());
        $project_image="";
            while($project_image_row = mysql_fetch_array($project_image_qry)) {
            $project_image_result =  mysql_fetch_array ($project_image_qry);    

                if($src=="true"){
                    $project_image .= '<img src="'.admin_settings('site_url').admin_settings('image_main_dir').'/'.$project_image_result['i_name'].'" alt="project_image"/>';   
                    }
                else{
                    $project_image .= $project_image_result['i_name'];
                    }
            }
        }
    return $project_image;
    }

解决方案

Your while condition is fine, but you seem to be fetching twice, in $project_image_row and $project_image_result, so you're going to be skipping every other image. Just fetch the array once (in the while loop is good), and use $project_image_result instead of $project_image_row within the loop to refer to that array:

while($project_image_result = mysql_fetch_array($project_image_qry)) {
    if($src=="true"){
        $project_image .= '<img src="'.admin_settings('site_url').admin_settings('image_main_dir').'/'.$project_image_result['i_name'].'" alt="project_image"/>';   
    }
    else{
        $project_image .= $project_image_result['i_name'];
    }
}

Also, it seems like by default you told it to only request one image from the database. You have a default parameter $limit=1, and you use an SQL LIMIT to filter the results, so unless you pass a fourth argument to get_project_image the mysql_query is only going to return one result (you didn't include the call to get_project_image, so I'm not sure if you handled that or not

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